This is a hard task. When I studied the research on students and synthesis tasks, I wasn't surprised to find that even college students struggle with it. Left to their own devices, students may copy information from texts, rely on a single text instead of referring to both, or engage in shallow thinking at the expense of true synthesis. (You can find the references here)
As I talked with students about their essays, I found that many were struggling with adding text quotations. One student tried to start the essay with two quotations from different texts, without any introductory phrases. Another added text quotations in the middle of paragraphs with no context. Another said, "I'm tired of using 'according to the text'. What else can I say?"
I realized that this was probably a skill that the whole class felt shaky with. Even though they've been writing passage-based essays for two years now, they are still not sure of how to integrate the text quotes into their own writing.
And there are so many things for writers to consider as they do this integration! My writers were struggling with
-How to choose the text quotations
-How to introduce the text quotations
-How to punctuate the text quotations
I started to remedy this with some read aloud. First, I chose Gary Blackwood's Enigmatic Events for its engaging content and great use of quotations from primary sources. Students need to hear much much more of the kind of academic writing that they are expected to do read aloud for them.
Then, I created a handout to guide a lesson about adding text quotations. (I love making handouts as lesson guides because they make catching up with co-teachers or kids who have been absent so easy.)
The handout shows different ways to introduce text quotes. In the first part, students underline the introductory words and phrases. In the second part, they figure out how to use the punctuation correctly by looking at examples.
We're still working on the best ways to add text quotations, but I feel that we're making progress! Next time--writing introductions.
You can find the handout for free at this link: Adding Text Quotations to Passage-Based Essays.